STATE AND EXPLAIN
💡 The Tier-2 topology description of a network can also include or imply the nature of the data flow through the network. And practical term used in professional training.
This is a hierarchical network design that consists of two layers: the Core Layer and the Access Layer. In this architecture, access switches connect directly to the core switch, which acts as the central backbone of the network. The access layer connects end devices such as computers, printers, IP phones, and wireless access points, while the core layer provides high-speed data forwarding and communication between different network segments. However, it has limited scalability compared to three-tier networks, so it is best suited for infrastructures with a moderate number of devices and manageable network traffic.
FAQ Execution
It simplifies network design and reduces cost while maintaining good performance for small and medium networks.
If access switches connect directly to a core switch without a distribution layer, the network is Tier-2.
The purpose is to provide efficient connectivity between users and the network backbone.
Use Tier-2 topology when: Network size is small or medium, Device count is less than 200–300, Simple management is required.
Indicators include: Limited number of switches, Single building network, Low traffic demand.
When: Network size is very large, Multiple campuses exist, Heavy traffic aggregation is required.
Because it offers: Simple architecture, Lower hardware cost, Easy troubleshooting.
Typical devices include: Core switches, Access switches, Routers, End devices.
The core layer provides high-speed backbone connectivity
The access layer connects end devices such as PCs, printers, and IP phones.
Each access switch connects directly to the core switch using uplinks.
Common cables include: Ethernet (Cat6 / Cat6A) and Fiber optic cables.
Steps:
1. Deploy core switch
2. Connect multiple access switches
3. Connect end devices to access switches
It depends on: Core switch port capacity and Network traffic load.
By adding additional access switches connected to the core.
VLANs are configured on access switches and trunked to the core switch.
Routing usually occurs at the core switch or router.
Redundancy can be achieved by: Dual uplinks and Link aggregation.
Examples include: STP (Prevent network loops), RSTP (Port Guard), VLAN trunking (Inter-Vlan).
Typically suitable for up to a few hundred devices.
Due to high oversubscription ratio.
By: Increasing uplink bandwidth and Adding additional core switches.
It increases uplink bandwidth and redundancy.
Common protocols include: Static routing and OSPF.
QoS policies prioritize critical traffic such as VoIP and video.
They provide routing between VLANs.
To detect: Traffic congestion, Link failures and Performance issues.
| Real Network | Real Infra |
|---|---|
| Enterprises Infra | Branch offices and Small campus networks. |
| Retail networks | POS systems, CCTV and Wi-Fi access points. |
| Town Hospitals | Medical devices, Workstations and Servers. |
| Educational Institutes | In computer labs and departmental networks. |
| Government Office | For internal office networks and document systems. |
Based on: Network size and Redundancy requirements.
Limited scalability and Single point of failure.
By adding a distribution layer between core and access switches.
Because it cannot efficiently handle large traffic volumes.
Data path:
End Device → Access Switch → Core Switch → Destination Switch
Data path:
End Device → Access Switch → Distribution Switch → Core Switch → Distribution → Destination
Tier-2: Routing occurs at core switch.
Tier-3: Routing occurs at distribution layer
Problems include: Broadcast storms, High latency, Core switch overload.
Aggregation refers to traffic collection, while distribution provides routing and policy control.
Traffic automatically reroutes through redundant distribution switches.
Typically 8 access switches per distribution switch.
Tier-2 topology will remain useful for small and medium networks, while large infrastructures will continue to adopt Tier-3 (spine-leaf architectures).
